Apparatus and method for percutaneous sealing of blood vessel punctures

ABSTRACT

A device for promoting hemostasis in a blood vessel puncture is employed with an introducer that accesses the puncture through an incision. The introducer has an open distal end positionable at the puncture, an external portion with an open proximal end, and an axial channel therebetween. The device includes a hollow catheter, dimensioned to pass through the introducer channel, having a distal end to which is attached an expansible compression element, which may be an inflatable balloon, a collapsible prong assembly, or a resilient foam pad. The compression element is collapsed when the distal end of the catheter is enclosed within the introducer. When the catheter and the introducer are located the desired distance from the puncture, the introducer is displaced axially relative to the catheter to expose the compression element to the subcutaneous tissue, whereupon the compression element is expanded. Pressure is applied to the compression element through the introducer to promote hemostasis by the compression of subcutaneous tissue adjacent the puncture. The device preferably includes a locator member passing into the blood vessel through the puncture. The locator member may be either a guide wire, or a hollow tube with a locating balloon, disposed near the portion of the tube insertable into the vessel. A dissolvable locating tip element, connected to the distal end of the catheter, may be used to maintain the position of the device while hemostasis takes place after the locator member is removed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.08/528,892; filed Sep. 15, 1995; issuing as U.S. Pat. No. 5,645,566.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of apparatus andmethods for sealing wounds in the blood vessels of humans or animals.More specifically, the invention relates to a guided vascularcompression device for percutaneously sealing arterial or venouspunctures subsequent to surgical procedures, by promoting in situhemostasis.

A large number of medical therapeutic and diagnostic procedures involvethe percutaneous introduction of instrumentation into a vein or artery.For example, percutaneous transluminal coronary angioplasty (PTCA), mostoften involving access to the femoral artery, is performed hundreds ofthousands of times annually, and the number of other suchvessel-piercing procedures performed, e.g., percutaneous coronaryangiography and atherectomy, has exceeded two million per year.

In each event, the closing and subsequent healing of the resultantvascular puncture is critical to the successful completion of theprocedure. Traditionally, the application of external pressure to theskin entry site by a nurse or physician has been employed to stembleeding from the wound until clotting and tissue rebuilding have sealedthe perforation. In some situations, this pressure must be maintainedfor half an hour to an hour or more, during which the patient isuncomfortably immobilized, often with sandbags and the like. Withexternally applied manual pressure, both patient comfort andpractitioner efficiency are impaired. Additionally, a risk of hematomaexists since bleeding from the vessel may continue until sufficientclotting effects hemostasis. Also, external pressure devices, such asfemoral compression systems, may be unsuitable for patients withsubstantial amounts of subcutaneous adipose tissue, since the skinsurface may be a considerable distance from the vascular puncture site,thereby rendering skin compression inaccurate and thus less effective.

More recently, devices have been proposed to promote hemostasis directlyat the site of the vascular perforation. One class of such puncturesealing devices features intraluminal plugs, as disclosed in U.S. Pat.Nos. 4,852,568--Kensey; 4,890,612--Kensey; 5,021,059--Kensey et al.; and5,061,774--Kensey. This class of device is characterized by theplacement of an object within the bloodstream of the vessel to close thepuncture.

Another approach to subcutaneous puncture closure involves delivery oftissue adhesives to the perforation site, as disclosed in U.S. Pat. No.5,383,899--Hammerslag. Some likelihood exists of introducing theadhesive so employed disadvantageously into the bloodstream. U.S. Pat.No. 4,929,246--Sinofsky discloses the concept of applying pressuredirectly to an artery, and relies on the directing of laser energythrough an optical fiber to cauterize the wound.

Yet another proposed solution to obviate the reliance on skin surfacepressure is disclosed in U.S. Pat. No. 5,275,616--Fowler, wherein acylindrical plug is inserted along the shaft of a catheter segmentextending from the skin surface to the blood vessel. The catheter isthen removed so that the plug can expand as fluid is drawn into the plugfrom the vessel and surrounding tissue. Unless pressure is applied,however, bleeding may occur around the plug into the subcutaneoustissue. Another approach that similarly deposits a plug into the tissuechannel is disclosed in U.S. Pat. No. 5,391,183--Janzen et al., whichdiscloses a variety of plug delivery devices including threaded plugpushers and multilegged channels. As in the other disclosed methods forintroducing a foreign plug into the incision, the Janzen et al. plugmaterial, generally resorbable, is not removed from the patient onceinstalled. Such permanent placement of foreign material into the bodymay result in inflammation or scar formation in the long term.

Furthermore, many of the prior art devices rely on tactile sensationalone to indicate to the surgeon the proper placement of the punctureclosing instrumentation, and may require upstream clamping of the bloodvessel to reduce intraluminal pressure to atmospheric at the puncturesite.

As the foregoing description of the prior art demonstrates, none of theheretofore proposed solutions fulfills the need for a relatively simple,non-cautery apparatus and method for subcutaneously applying pressuredirectly to the vicinity of the vessel puncture by means of a pressureelement that is removed from the patient once sealing of the puncture isachieved. There is a further need for a puncture sealing system thatfeatures use of instruments already in place at the access site so thatthe position for possible reentry is not lost, and the time required forthe physician to change instrumentation is minimized. There is a stillfurther need for a system that maintains pressure on the puncture siteby lightweight mechanical means, thereby relieving the patient from thediscomfort of external compression means, and freeing hospital personnelfrom constant surveillance of cumbersome external pressure structuresfor the duration of the hemostasis. There is also a need for ahemostatic device that can be effectively employed regardless of thethickness of the tissue between the skin and the puncture site, byapplying localized pressure close to the puncture site, rather thanremote, diffused pressure to the skin surface.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a method and apparatus forsealing post-surgical vascular punctures that overcome the foregoingdeficiencies.

It is a further object to apply pressure directly to the vicinity of thevascular puncture access site utilizing a subcutaneous pressure elementthat is removed permanently from the patient once hemostasis isachieved.

It is another object to employ an introducer instrument already in placeat the access site to minimize instrumentation changing time, and tomaintain access during an initial clotting period to facilitate possiblereentry.

It is yet another object to maintain adequate hemostatic pressure on anadipose or fatty tissue layer above the puncture site in order to closethe puncture naturally, to reduce the potential for pseudo-aneurysmformation, and to maintain such pressure by lightweight, non-laborintensive, mechanical means, thereby reducing patient discomfort.

The present invention involves a method for sealing a puncture site in ablood vessel, and apparatus for performing that method, wherein use ismade of an introducer sheath (commonly referred to in the medicalcommunity as an "introducer") which is usually already in place insidethe puncture site when a medical practitioner has completed a procedurethat requires intravascular access. Locator means, preferably either alocator tube (having an inflatable locating balloon), or a standardguidewire, is passed through the introducer and into the lumen of thevessel. Alternatively, a dissolvable locating tip can be provided at thedistal end of the catheter. The locating tip is inserted into the lumenof the vessel, using a guidewire, and maintains the distal end of thecatheter in its proper position in the puncture site.

A semi-rigid catheter, including an expandable compression element atits distal end, and either two axial lumens (used in a compressionballoon embodiment) or a single axial lumen (used in other embodiments),is inserted along the locator means fully into the introducer so thatthe expandable compression element at the distal end of the catheter iscontained in an unexpanded state within the distal end of the introducerwhen the introducer is in a first or distal position relative to thecatheter.

The introducer and the catheter are partially withdrawn together (movedproximally) from the puncture site until a preferred location above thevessel is achieved, the relative axial positions of the introducer andthe catheter remaining unchanged, so that the introducer remains in itsfirst or distal position relative to the catheter. This location ischosen to provide for a layer of fatty tissue above the puncture sitebetween the compression element and the vessel. The extent of partialwithdrawal is determined by the tactile sense of the practitioner, aidedby a marker on a locator tube for the embodiment employing a locatingballoon as the locator means, or by fluoroscopic viewing of a contrastmedium, for the embodiments employing a guidewire (with or without adissolvable locating tip) as the locating means.

When the location is achieved, the introducer is moved to a second orproximal position relative to the catheter until the expandablecompression element is revealed and expanded to bear on the fatty tissuelayer.

In another embodiment, the expandable compression element comprises anexpandable prong assembly including a resilient spanning sheet forcompressing the fatty tissue layer. In still another embodiment, theexpandable compression element comprises a foam pad element bearingdirectly on the fatty tissue layer upon expansion when deployed from theintroducer.

Once the compression element (balloon, prongs or foam tip) is in place,a lightweight holding arrangement is employed to maintain hemostaticpressure. The holding arrangement comprises an adhesive skin patch andfastener strips or bands bringing downward pressure on a sheath cuffclamped to the introducer. After an initial period of hemostasis,(approximately one to five minutes), the locator means (locator balloontube or guidewire) is removed from the puncture and the apparatus. Afteranother five to twenty-five minutes of pressure on the puncture, theexpandable distal end element (compression balloon, prongs or foam) iscollapsed, and the introducer and catheter are permanently removed fromthe patient.

These and other features and advantages of the present invention will bemore readily apparent from the Detailed Description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view, partially in cross section, illustratinga first preferred embodiment of the present invention;

FIG. 1A is an elevational view, partially in cross section, illustratingthe initial position in a puncture site of the distal portion of theapparatus of FIG. 1;

FIG. 1B is an elevational view, partially in cross section, illustratingthe apparatus of FIG. 1A in a preferred operational position;

FIG. 1C is an elevational view, partially in cross section, illustratingthe apparatus of FIG. 1A with the compression balloon revealed and notyet inflated;

FIG. 1D is a cross sectional view taken along lines 1D--1D of FIG. 1,illustrating the dual lumen configuration of a catheter element of theapparatus of FIG. 1;

FIG. 2 is an elevational view, partially in cross section, of a secondpreferred embodiment of the present invention, showing the compressionmechanism of this embodiment in a retracted state near a vascularpuncture site;

FIG. 2A is a perspective view of the embodiment of FIG. 2, showing thecompression mechanism in an expanded state;

FIG. 2B is a view similar to that of FIG. 2, showing the compressionmechanism deployed, in its expanded state, at a vascular puncture site;

FIG. 3 is an elevational view, partially in cross section, of a thirdpreferred embodiment of the present invention, showing the compressionmechanism of this embodiment in a retracted state near a vascularpuncture site;

FIG. 3A is a view, similar to that of FIG. 3, illustrating thecompression mechanism in an expanded state;

FIG. 4 is a perspective view of a fourth preferred embodiment of thepresent invention;

FIG. 4A is an elevational view, partially in cross section, illustratingthe initial position in a puncture site of the introducer and guidewireelements of the apparatus of FIG. 4;

FIG. 4B is a view similar to that of FIG. 4A, but showing a cathetercontained within the introducer when the introducer is in a first axialposition relative to the catheter;

FIG. 4C is an elevational view, partially in cross section, illustratingthe apparatus of FIG. 4A in a preferred operational position;

FIG. 4D is an elevational view, partially in cross section, illustratingthe apparatus of FIG. 4A with the compression balloon revealed and notyet inflated, the introducer having been moved to a second axialposition relative to the catheter;

FIG. 4E is a perspective view, partially in cross section, illustratingthe compression balloon of the apparatus of FIG. 4D in an inflatedstate;

FIG. 4F is an elevational view, partially in cross section, illustratingthe apparatus of FIG. 4E with the guidewire element withdrawn;

FIG. 5 is an elevational view, partially in cross section, illustratinga modification of the embodiment of FIG. 1;

FIG. 6 is an elevational view of a modification of the fourth preferredembodiment of FIGS. 4 through 4F, having an optional dissolvablelocating tip at the distal end of the catheter;

FIG. 7 is an elevational view of the modified fourth preferredembodiment of FIG. 6, showing the present invention deployed at avascular puncture site, with the locating tip inserted into the lumen ofa blood vessel;

FIG. 8 is an elevational view of a modification of the third preferredembodiment of FIGS. 3 and 3A, having an optional dissolvable locatingtip; and

FIG. 9 is an elevational view of an alternative form of a dissolvablelocating tip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

1. Structure of the Apparatus

A percutaneous blood vessel sealing device, or percutaneous hemostaticdevice 10, which applies hemostatic sealing pressure directly to tissueadjacent a vascular puncture site, without employing implantedmaterials, is shown in FIG. 1.

In each exemplary embodiment described herein, an introducer sheath("introducer") 12, well known in the art, is present in an incision 14that extends from the skin surface 16 to a blood vessel (artery or vein)18 of a patient at the site of a blood vessel puncture 20. Theintroducer 12 has normally been inserted previously to provide access tothe vessel 18 for instrumentation (not shown) used in performing avascular procedure immediately preceding the need to seal the puncture20. The initial position of an introducer 12 so inserted is most clearlyillustrated in FIG. 4A, which shows a tapered distal end 22 of theintroducer 12 at a puncture site 24, inserted within a vascular puncture20. Typically, the introducer 12 will have a size of approximately 7French (2.3 mm in diameter), and a length of approximately 130 mm,although a size as large as 14 French (4.7 mm in diameter) may be usedfor larger punctures.

A working channel 26, best seen in FIG. 1D, extends axially from theproximal end 28 of the introducer 12 through its tapered distal end 22.In the first preferred embodiment of FIGS. 1 through 1D, a hollowlocator tube 30 extends coaxially through the introducer 12 and into thevessel 18 through the puncture 20. Guided by the locator tube 30 intothe introducer working channel 26 is a semi-rigid catheter 32 having acatheter proximal end 33, and a catheter distal end 34 (FIG. 1A). Theintroducer 12 is movable axially with respect to the catheter 32, and isdisposed initially at a first axial position, or distal position, inwhich the catheter distal end 34 is enclosed or sheathed within thedistal end 22 of the introducer 12.

The catheter 32 is a dual-lumen device having a first axial lumen 36(FIG. 1D) which encompasses the locator tube 30 when the catheter 32 isinserted into the working channel 26 of the introducer 12. A secondaxial lumen 38 is provided with an inflation orifice 40 near its distalend, the inflation orifice communicating with the interior of acompression balloon 42 that concentrically surrounds a portion of thelength of the catheter 32 extending proximally from its distal end 34.The compression balloon 42 is initially enclosed, in an uninflatedstate, within the distal end 22 of the introducer 12, as illustrated inFIG. 1A. The opposite (proximal) end of the second axial lumen 38communicates with a compression balloon inflation port 44 through aninflation tube 45, as shown in FIGS. 1 and 4. Overall, the catheter 32has an outer diameter sufficiently small to be freely insertable intothe introducer 12, and a length that is greater than that of theintroducer 12, i.e., in the range of about 130 mm to about 750 mm.

At the proximal end 28 of the introducer 12 is a well-known luer typelock fitting 46 configured to mate with a catheter proximal end luerfitting 48 when the introducer 12 and the catheter 32 are in a finaloperational position, as determined by manipulation of the locator tube30, as will be described below. The locator tube 30 has an inflatableintravascular locating balloon 50 at its distal end portion, shown inFIG. 1A in an uninflated state. The interior of the locating balloon 50is in fluid communication with the hollow interior of the locator tube30 through a suitable inflation orifice (not shown), as is well known inconventional balloon catheters and the like.

Although the luer locks 46, 48 may be employed for both the locatorballoon embodiment (FIGS. 1 through 1D) and for embodiments (describedbelow) featuring expandable compression elements other than thecompression balloon 42, a version using no luer locks will be describedbelow that is specifically adapted for use with the compression balloon42. Both the luer and non-luer versions are suitable for embodimentsemploying either the inflatable locating balloon 50 or a guidewirelocating means, to be described below.

Returning now to FIGS. 1A through 1C, a progression of locatingpositions for the device 10 is illustrated. FIG. 1A shows the locatortube 30, having the uninflated locating balloon 50 near its distal end,inserted into the vessel 18 through the introducer 12 and the vascularpuncture 20. It is advantageous to construct the locator tube 30 so thata length of tube extends distally beyond the location of the locatingballoon 50 into the vessel 18 to facilitate re-access through thevascular puncture 20, if required. The entire apparatus 10 (includingthe introducer 12 and the catheter 32) is in its initial positionrelative to the vessel; that is, the distal tip 22 of the introducer 12is located adjacent to or within the puncture 20, while the introducer12 is in its above-described first axial position or distal positionrelative to the catheter 32, in which the catheter distal end 34 and theuninflated compression balloon 42 are enclosed within the distal end 22of the introducer 12.

FIG. 1B illustrates the device 10 after the locating balloon 50 has beeninflated by fluid introduced into it via the locator tube 30. The entiredevice 10 (including the introducer 12 and the catheter 32) has beenpartially withdrawn from the puncture site 24 in the direction of thearrow 52 (i.e., in the proximal direction), to a "preferred operationalposition", in which the locating balloon 50 is lodged against aninterior wall 54 of the vessel 18. The introducer 12 remains in itsfirst or distal position, in which the portion of the catheter 32carrying the uninflated compression balloon 42 is enclosed within thedistal end 22 of the introducer 12.

In FIG. 1C, the introducer 12 has been moved axially, relative to thecatheter 32, in the direction of the arrow 52 (i.e., proximally), to itssecond axial position, or proximal position. The movement of theintroducer 12 to this second or proximal position uncovers theuninflated compression balloon 42.

The compression stage of the device 10 is illustrated next in FIG. 1.The compression balloon 42, inflated via the second axial lumen 38 (FIG.1D), rests in an optimal position to effect natural hemostasis, viz.,above a laminar portion 56 of the fatty tissue adjacent the puncturesite 24. An optimal distance from the vessel 18 to the catheter distalend 34 is in the range of 2 mm to 10 mm. This distance will dispose alayer of fatty tissue 56 between the vessel 18 and the catheter 32,minimizing the potential for pseudo-aneurysm. The introducer luer lock46 is shown engaged with the catheter luer lock 48, assuring that aholding force applied to the introducer 12 will be transmitted as wellto the catheter 32. In addition, a visible marker band 57 on theexterior of the locating tubing 30 may advantageously be provided toalign the proximal ends of the introducer 12 and the catheter 32 incorrespondence with the location of the distal ends 22, 34 thereof whenthe locator balloon 50 is lodged against the inner wall 54 of vessel 18.

An adhesive skin patch 58 with a sheath cuff 60 clamped onto theexternal portion of the introducer 12 to apply downward force (in thedirection of the arrow 62, i.e., distally) on the introducer 12 is shownin FIGS. 1 and 4. Fastener strips 64 secure the adhesive patch 58 to thesheath cuff 60. The fastener strips 64 may be elastic bands withsuitable adhesive areas, or hook and loop strips (such as the typemarketed under the trademark VELCRO) that adhere to areas ofcomplementary material on the patch 58. Pressure maintained by theintroducer sheath cuff 60 on the catheter 32 provides hemostaticpressure on the compression balloon 42 to bear on the tissue layer 56for a first period of time, whereupon the locating tube 30 is withdrawn(the locator balloon 50 having first been deflated), and a second periodof time elapses, after which all instrumentation is removed from thepatient as will be noted when the method for sealing the puncture 20 isdescribed in detail below.

Another embodiment of the present invention is illustrated in FIGS. 2,2A, and 2B, which show a collapsible prong assembly compression element66 attached to the catheter distal end 34. The prong assembly 66 isradially compressed or collapsed when enclosed within the introducer 12,when the introducer is in its first or distal position. The prongassembly 66 expands radially when the introducer 12 is partiallywithdrawn from the vessel 18 (FIGS. 2A and 2B), by moving the introducer12 to its second or proximal position in a manner similar to the partialwithdrawal of introducer 12 in the direction of arrow 52 as describedpreviously in connection with the compression balloon embodiment.

The prong assembly 66 comprises a plurality of spaced-apart resilientprongs 68, the proximal ends of which are attached to the catheter 32,and the distal ends of which are attached to a collapsible spanning filmsheet or dam 70, shown expanded in FIGS. 2A and 2B. The sheet or dam 70allows the application of hemostatic pressure on the tissue 56 above thevessel 18. A central aperture 72 in the sheet or dam 70 permits thelocator tube (not shown) to project through the catheter 32 into thevessel 18 as described previously. Since there is no compression balloonto be inflated, a catheter with a single axial lumen 36 is adequate forthis application. Materials for the spanning sheet or dam 70 may includepolyurethane and polyethyleneterephthalate (PET).

Still another embodiment of the invention is illustrated in FIGS. 3 and3A, which show a foam pad compression element 74 attached to thecatheter distal end 34. The foam pad element 74 is compressed whenenclosed within the introducer 12 when the introducer is in its first ordistal position. The foam pad compression element 74 then expands whenthe introducer 12 is partially withdrawn from the vessel 18, as shown inFIG. 3A, by moving the introducer 12 to its second or proximal position,as described above with respect to the first and second embodiments.Hemostatic pressure is similarly exerted on the tissue 56 above thevessel 18. An axial channel 76 in the foam pad 74 permits the locatortube (not shown) to project through the catheter 32 into the vessel 18,as described previously. As with the expanding prong embodiment above,since there is no compression balloon to be inflated, a catheter with asingle axial lumen 36 is adequate for this embodiment. Materials for thefoam pad 74 may include various polymeric foams, such as polyurethanes,as are well-known in the art. The foam pad 74 may be impregnated with acoagulant such as thrombin or protamine to effect local hemostasis.

The foregoing embodiments, featuring both the luer locking of theintroducer 12 with the catheter 32, and a variety of expandablecompression elements 42, 66, 74 at the catheter distal end 34, employ alocator tube 30 with a locating balloon 50 to determine the optimaloperational location for the apparatus 10. In lieu of a locating balloon50, a guidewire 78 may be utilized for the location determination of theapparatus 10, as illustrated in FIGS. 4 through 4F.

In FIG. 4A, a standard guidewire 78, typically 3 French (1 mm indiameter), shown coaxially located within the introducer 12, has adistal end 82 extending out of the introducer distal end 22 into thepuncture 20 of the vessel 18.

The catheter 32 is shown in FIG. 4B having been inserted into theintroducer 12 and guided to the distal end 22 of the introducer by theguidewire 78. At the distal end 34 of the catheter 32 is a radiopaquemarker 84 for viewing under fluoroscopy, as shown in FIG. 4D.

FIG. 4C shows an optimal location for catheter distal end 34, radiopaquecontrast medium (not shown) having been introduced into the catheterlumen 36, and the apparatus 10 having been partially withdrawn from thevessel 18 in the direction of the arrow 52 (i.e., proximally). Anextravasation 85 of the radiopaque contrast medium is shown marking thedesired distance between the vessel 18 and the catheter distal end 34,as will be explained when the method for sealing the puncture isdescribed below.

The introducer 12 is shown in FIG. 4D having been moved, in thedirection of the arrow 52, to its second or proximal position to revealthe uninflated compression balloon 42 in position for inflating. FIG. 4Eillustrates the apparatus 10 with the compression balloon 42 inflatedand in place above the fatty layer 56 to apply hemostatic pressure for afirst period of time in order to effect initial closure of puncture site24. FIG. 4F shows the apparatus 10 after the guidewire 78 has beenremoved from the apparatus 10 and pressure is applied for a secondperiod of time to close the puncture 20.

In analogous fashion, the guidewire 78 and radiopaque positioning of anexpandable compression element at the distal end 34 of the catheter 32may be employed with the prong assembly and foam pad embodimentsdescribed above in connection with the locator tube 30. For introducingthe radiopaque or contrast medium (not shown) into the catheter lumen36, a standard hemostatic "Y" 86 is used, as shown in FIG. 4. The "Y" 86has a main leg 88 for receiving the guidewire 78 into the axial lumen 36of the catheter 32, while a side port 90 of the "Y" 86 is used forintroducing the contrast medium into the same lumen.

A modification of the first (compression balloon) embodiment of thepresent invention is shown in FIG. 5, where an apparatus 110 has anintroducer 112 having no luer connection with a catheter 132. Since thecuff 60 applies downward force in the direction of the arrow 62 only tothe introducer 112, and not to the catheter 132, the distal end 122 ofthe introducer 112 must bear directly on the compression balloon 42 toexert hemostatic pressure on the balloon 42. Although this modificationis suitable only for the compression balloon embodiment of thisinvention, both the locator tube 30 and the guidewire 78 may be utilizedin this modification for optimal positioning of the catheter distal end34.

FIGS. 6 and 7 illustrate a modification of the fourth preferredembodiment (that of FIGS. 4 through 4F). In accordance with thismodification, a dissolvable or resorbable locating tip element 140 isfixed to the distal end 34 of the catheter 32, distally from thecompression balloon 42. The locating tip element 140 is an elongate,tubular member, having a generally cylindrical main portion 142 and atapered distal end tip 144. The diameter of the cylindrical main portion142 is preferably about 1.3 to 4.0 mm, and the overall length of thelocating tip 140 element is preferably about 1 to 4 cm, the dimensionsof a particular locating tip 140 being selected in accordance with suchfactors as the dimensions and location of the puncture site, its "dwelltime" (see below), and the preferences of the physician. The locatingtip 140 element is hollow and open-ended to allow the guidewire 78 topass through it.

The locating tip element 140 is preferably used in conjunction withlocating means such as the guidewire 78 or the locator tube 30. As shownin FIG. 7, the locating tip element 140 is dimensioned so that it can beinserted into the blood vessel lumen 18 through the puncture site 20,and maintains the location of the apparatus 10 during use, after theguidewire 78 has been withdrawn (see below). The locating tip element140 is made of a material that is biocompatibly (non-toxically)dissolved in the blood stream during a period of between about 10 and 60minutes (the "dwell time"), during which time partial resorption of thematerial into the subcutaneous tissue results in the detachment of thelocating tip element 140 from the catheter 32. The detachment leaves aportion of the locating tip element 140 outside of the blood vessel, tobe completely dissolved into the subcutaneous tissue.

Suitable materials for the locating tip element 140 may include, forexample a number of well-known polymers, methyl cellulose, carboxymethylcellulose, carbowaxes, and gelatin (particularly pigskin gelatin). Amongthe suitable polymers are polylactic glycolic acids, polyvinylpyrrolidone, polyvinyl alcohol, polyproline, and polyethylene oxide.

The dissolvable locating tip element 140 may be employed with otherembodiments of the invention, particularly the compressible foam padembodiment of FIGS. 3 and 3A. In this embodiment, as shown in FIG. 8, afoam pad 74' is attached to the distal end 34 of the catheter 32, andhas a distal end 146. A dissolvable locating tip element 140', of thetype described above, is attached to, and extends distally from, thedistal end 146 of the foam pad 74'.

It will be appreciated that the dissolvable locating tip element 140,140' may be modified and adapted for use as a locating tip for cathetersand other devices that may be used in a wide variety of applications.For example, an alternative dissolvable locating tip element 150 isshown in FIG. 9. In this alternative form, the dissolvable locating tipelement 150 comprises a cylindrical portion 152 attached to the distalend of a surgical instrument 154 (e.g., a catheter). Projecting distallyand coaxially from the cylindrical portion 152 is a slender tubularportion 156, terminating in a tapered distal end tip 158. The distal endof the cylindrical portion defines an annular shoulder 160 surroundingthe juncture with the tubular portion 156. The entire dissolvablelocating tip 150 may have an axial passage 162 through its length toreceive a guidewire or the like (not shown).

The dissolvable locating tip element 150 of FIG. 9 may be inserted intoa puncture site in a blood vessel, in the manner similar to thatdiscussed above with respect to FIGS. 6 and 7. In this embodiment,however, only the distal tip end 158 and an adjacent portion of thetubular portion 156 enter the blood vessel. The cylindrical portion 152remains outside the vessel, with the shoulder 160 functioning as acompression element, much as does the foam pad 74, 74', described abovein connection with FIGS. 3, 3A, and 8. In this case, the compressionelement, being integral with and of the same dissolvable material as thelocating tip, likewise dissolves in the patient's tissue afterhemostasis has occurred.

2. Method for Sealing Vascular Punctures

A brief review of a typical vascular entry procedure may be of value indescribing the puncture closure technique of the present invention. Toinitiate one of the common operations such as the PTCA (PercutaneousTransluminal Coronary Angioplasty) mentioned above, a piercing cannulais inserted into the skin of a patient at an angle of from 25 to 45degrees until it punctures a blood vessel, e.g., the femoral artery. Thevessel may be located one centimeter or more beneath the surface of theskin. A guidewire is inserted through the cannula into the vessel, thecannula is withdrawn, and a catheter introducer sheath is inserted overthe guidewire into the puncture site.

The practitioner then uses the introducer to gain access to the vascularlumen for the instrumentation used to perform the particular procedure.At the conclusion of the procedure, the introducer is the last deviceremaining in the puncture, which must then be sealed.

The method of the present invention provides a rapid, permanent,inexpensive sealing of a puncture in a blood vessel, with no foreignimplants remaining in the patient. The method can be understood withreference to the drawing figures and the previous description of theapparatus of this invention.

In FIG. 1A, an introducer sheath 12 is shown in a puncture site 24 atthe conclusion of a vascular procedure. According to one embodiment ofthe present invention, a locator tube 30 having an inflatable locatingballoon 50 adjacent its distal end is inserted axially through theintroducer 12, into a puncture 20 and extending the uninflated locatingballoon 50 into the lumen of a vessel 18.

A dual lumen catheter 32 is passed over the locator tube 30 so that afirst lumen 36 (FIG. 1D) of the catheter 32 receives the locator tube30. The locator tube 30 maintains alignment of the catheter 32 with thepuncture 20 and allows repeated access into the vessel 18, if necessary.The catheter 32, having an inflatable compression balloon 42 at itsdistal end 34, is inserted fully into the introducer 12 until its distalend 34, including the uninflated compression balloon 42, is at thedistal end 22 of the introducer 12. At this stage, the locator tube 30is pushed or pulled until a marker band 57 (shown in FIG. 1) is alignedwith the proximal end 33 of the catheter 32. The marker band 57 ispreselected to establish a fixed relationship with the catheter 32 sothat a preferred distance may be maintained between the vessel 18 andthe distal end 34 of catheter 32 as will be explained below. Theintroducer 12 being in its first or distal position, the uninflatedcompression balloon 42 is fully enclosed and contained within theworking channel 26 of the introducer 12, as described above.

The practitioner then inflates the locating balloon 50 via the locatortube 30, partially withdrawing the introducer 12, the catheter 32 andthe locator tube 30 from the puncture 20 in the direction of the arrow52, until the locating balloon 50 lodges against the inner wall of thevessel 18 at the puncture 20, as illustrated in FIG. 1B. Since theposition of the catheter distal end 34 relative to the introducer distalend 22 remains unchanged, the distal end 34 of the catheter is now atthe location predetermined by the placement of the marker band 57,preferably about 5 mm to 15 mm from the puncture 20. This distance willallow a layer of fatty subcutaneous tissue 56 to lie between thecatheter distal end 34 and the puncture 20.

Once the catheter distal end 34 is in the desired location, theintroducer 12 is further withdrawn in the direction of the arrow 52, bymoving it to its second or proximal position relative to the catheter32, as described above, to expose the uninflated compression balloon 42,as shown in FIG. 1C. The luer fittings 46, 48 at the proximal ends ofthe catheter 32 and the introducer 12, respectively, are now connectedto each other to lock the catheter 32 and the introducer 12 into a fixedposition relative to one another, and the compression balloon 42 is theninflated, as illustrated in FIG. 1, via a second catheter lumen 38 (FIG.1D). The compression balloon 42 is then pressed down against the fattylayer 56 above the puncture site 24, while gentle traction is maintainedon the locating balloon 50, thus compressing the extravascular fattytissue 56 between the balloons 42, 50. The fatty tissue 56advantageously minimizes the potential of pseudo-aneurysm formation andpromotes efficient hemostasis.

To assist in maintaining pressure on the vessel 18, an introducer cuff60 is clamped onto the introducer 12 and secured to an adhesive patch 58by means of elastic or hook and loop fastening strips 64 (FIGS. 1 and4). When the introducer 12 is locked with the catheter 32 by the luerfittings 46, 48, the downward force provided by the fastening strips 64is transmitted from the introducer 12 through the semi-rigid catheter 32to the compression balloon 42, maintaining hemostatic pressure on thepuncture site 24 through fatty tissue 56.

After a first period of time (approximately 5 to 15 minutes), initialclotting of the puncture 20 will have occurred. The locating balloon 50is then deflated and the locator tube 30 withdrawn from the apparatus10, leaving only a small (e.g., approximately 1 mm in diameter) portionof the original puncture 20 to clot. The compression balloon 42 remainsin place for an additional (second) period of time (approximately 5 to25 minutes), providing hemostasis to the puncture 20, after which thecompression balloon 42 is deflated and retracted proximally into theintroducer 12, the luer fittings 46, 48 having first been disconnected.The sealing process having been completed, the apparatus 10 iscompletely removed from the patient.

The foregoing method uses an introducer 12 that is already positioned atthe access site so that position is not lost in changing instruments,bleeding does not occur while devices are positioned, and the locatortube 30 maintains the access location for re-access if needed during theinitial clotting of the puncture 20. Furthermore, employment of thepresent invention requires minimal physician time and greatly reducesstaff time and involvement previously devoted to maintaining supradermalpressure for long periods of hemostasis. In addition, the need foroperating room time may be reduced by the removal of the locator tube30, the introducer 12 and the catheter 32 after the patient is returnedto the patient's room. Overall, patient discomfort is significantlylessened through the use of the foregoing method as compared with thetraditional manual external compression techniques.

Similar steps are followed for implementing the method of the presentinvention with the second embodiment of the apparatus described above.In the second embodiment, the compression element at catheter distal end34 comprises the collapsible prong assembly 66, as shown in FIGS. 2, 2A,and 2B. In this second embodiment, once the introducer distal end 22 isin its initial (first or distal) position (about 5 to 15 mm from thevessel 18) as shown in FIG. 2, the movement of the introducer 12 to itssecond or proximal position releases the prong assembly 66 fromconfinement within the introducer 12, allowing the individual prongs 68of the prong assembly 66 to expand, as illustrated in FIG. 2A. Aresilient spanning sheet or dam 70, supported by the ends of the prongs68, then allows the application of hemostatic pressure on the fattytissue layer 56, as described earlier in connection with the compressionballoon embodiment. The locator tube (not shown) passes through and iswithdrawn from the aperture 72 in the spanning film 70.

A third embodiment of the method, following steps substantiallyidentical to the above described procedures, involves the use of thecompressible foam pad 74 shown in FIGS. 3 and 3A as the compressionelement at the distal end 34 of the catheter 32.

In this third embodiment, when the catheter 32 is in the preferredlocation as shown in FIG. 3, the introducer 12 is moved from its firstor distal position to its second or proximal position (in the directionof the arrow 52) to uncover the foam pad 74, allowing it to expand, asillustrated in FIG. 3A. The expanded foam pad 74 exerts hemostaticpressure upon the fatty tissue layer 56, as described previously. Thelocator tube (not shown) passes through and is withdrawn from the padchannel 76 formed axially in the foam pad 74. If deemed desirable by thepractitioner, a coagulant agent such as collagen, thrombin or protaminemay be delivered to the vicinity of the puncture site through the padchannel 76 which communicates with the catheter axial lumen 36.Alternatively, the foam pad 74 may be saturated with the agent prior todeployment.

The method employed with the apparatus described above may also use aguidewire 78 (FIG. 4) to perform the locating functions provided by thelocator tube 30 in the previous embodiments. All three of thecompression elements, viz., the compression balloon 42, the expandableprong element 66 and the foam pad 74, may be utilized with the guidewire78. For purposes of illustration, FIGS. 4 through 4F, showing only thecompression balloon 42 alternative, may be viewed with the understandingthat the method to be described in conjunction therewith applies to allthree guidewire 78 embodiments.

Referring now to FIG. 4A, the introducer 12 is shown as it remains inthe puncture 20 after a vascular access procedure. A conventionalsurgical guidewire 78 is extended through the introducer 12 so that itsdistal end 82 extends into the lumen of the vessel 18. The dual lumencatheter 32 is passed over the guidewire 78 so that a first lumen 36(FIG. 1D) of the catheter 32 receives the guidewire 78. The guidewire 78maintains alignment of the catheter 32 with the puncture 20 and allowsre-access into the vessel 18 if it becomes necessary. As describedearlier, the catheter 32, having an inflatable compression balloon 42 atits distal end 34, is inserted fully into the introducer 12 until itsdistal end 34, including the uninflated compression balloon 42, isenclosed within the working channel 26 at the distal end 22 of theintroducer 12, as shown in FIG. 4B.

A radiopaque contrast medium (not shown) is introduced into the catheterfirst lumen 36, as illustrated in FIG. 4. A main leg 88 of aconventional hemostasis "Y" 86 may be passed over the guidewire 78 andattached to the proximal end 33 of the catheter lumen 36. The contrastmedium is then introduced into the catheter lumen 36 via a side port 90of the "Y" 86, and viewed by the practitioner using conventionalfluoroscopic techniques. To aid in locating the position of the catheterdistal end 34, a radiopaque marker 84 may be provided at the tip of thecatheter distal end 34 (FIG. 4D).

As the practitioner views the vascular scene under fluoroscopy, theintroducer 12 with the catheter 32 is partially withdrawn in thedirection of the arrow 52 from the puncture 20. Withdrawal is continueduntil contrast medium in the catheter lumen 36 escaping from around theguidewire 78 into the vessel 18 is observed to form an extravasationcloud 85, signifying that the introducer 12 and the catheter 32 haveexited the puncture 20. When the practitioner is satisfied throughfluoroscopy that the catheter distal end element 34 is the preferreddistance of about 5 to 15 mm from the vessel 18, withdrawal of thecatheter 32 is halted, as shown in FIG. 4C.

The remainder of the closure procedure is essentially the same asdescribed above after the preferred position of the catheter 32 wasdetermined through the locator tube 30 method. The introducer 12 ismoved from its first or distal position relative to the catheter 32 toits second or proximal position, to expose the uninflated compressionballoon 42, as shown in FIG. 4D. The compression balloon 42 is theninflated to bear on the fatty tissue layer 56 as shown in FIG. 4E. Thelocating means (in this embodiment guidewire 78) is then withdrawn fromthe apparatus after an initial period of clotting (FIG. 4F). As notedpreviously, the method employing the guidewire 78 may be effectivelyadapted for use with the expandable prong element and foam tipembodiments of the present invention.

Still another method of the invention is illustrated in FIG. 5, whereinthe apparatus 110 differs from the apparatus 10 in that the introducer112 and the catheter 132 are not luer-locked together. FIG. 5 shows theposition of the catheter 132 aligned with a visible marker band 57 onthe locator tube 30, just as in the first embodiment described above. Itwill be readily understood that the method of this "luerless" apparatus110 may be equally utilized with the guidewire 78 as with the locatortube 30 for the compression balloon embodiment of this invention.

When the preferred location of the expanded compression balloon 42 hasbeen achieved as shown in FIG. 5, by applying either the guidewire orthe locator tube methods previously explained, force must be appliedfrom above to the compression balloon 42 to maintain hemostatic pressureon the fatty tissue layer 56. The practitioner advances the introducer112 downward in the direction of the arrow 62 until the introducerdistal end 22 makes contact with the surface of the compression balloon42. This hemostatic pressure is then maintained by securing theintroducer sheath cuff 60 to the skin patch 58 via the fastener stripsor bands 64. It will be noted that no downward pressure is being exertedon the catheter 132 itself, since it has no mechanical interlock withthe introducer 112, as in the previous described embodiments.

Although certain exemplary embodiments of the invention have beendescribed hereinabove, it will be appreciated that a number ofvariations and modifications may suggest themselves to those skilled inthe pertinent arts. For example, a coagulant agent may be applied to anyof the above-described compression elements. Such variations andmodifications are considered within the spirit and scope of theinvention as defined in the claims that follow.

What is claimed is:
 1. A locating device for a catheter employed toprovide percutaneous sealing of a puncture in a blood vessel throughwhich a bloodstream flows, the catheter having a distal end locatableadjacent the puncture, the device comprising:a locating elementattachable to the distal end of the catheter so as to extend distallytherefrom, the locating element being dimensioned to permit its entryinto the puncture, the locating element being formed from abiocompatible material that dissolves in the bloodstream.
 2. Thelocating device of claim 1, wherein the locating element comprises atubular portion dimensioned to permit its entry into the puncture. 3.The locating device of claim 1, wherein the locating element comprises:acylindrical portion attachable to the distal end of the catheter; and atubular portion extending distally from the cylindrical portion, therebydefining a shoulder at the juncture between the tubular portion and thecylindrical portion, the tubular portion being dimensioned to permit itsentry into the puncture.
 4. The locating device of claim 1, wherein thelocating element dissolves in the bloodstream during a period ofapproximately ten to sixty minutes.
 5. The locating device of claim 4,wherein the locating element is made of a material selected from thegroup consisting of methyl cellulose, carboxymethyl cellulose, carbowax,gelatin, polylactic glycolic acids, polyvinyl pyrrolidone, polyvinylalcohol, polyproline, and polyethylene oxide.
 6. The locating device ofclaim 3, wherein the locating element dissolves in the bloodstreamduring a period of approximately ten to sixty minutes.
 7. The locatingdevice of claim 6, wherein the locating element is made of a materialselected from the group consisting of methyl cellulose, carboxymethylcellulose, carbowax, gelatin, polylactic glycolic acids, polyvinylpyrrolidone, polyvinyl alcohol, polyproline, and polyethylene oxide. 8.The locating device of claim 7, further comprising:an expandablecompression member located on the catheter proximal of the locatingelement for sealing the puncture in the blood vessel.